The present invention relates to toroidal coil winding machines.
At the present time conventional coil winding machines for winding a toroidal core (bobbin) generally use a shuttle magazine mechanism ("shuttle") in the form of a ring having an opening which fits through the hole of the core. A supply of wire is loaded in the shuttle in the form of a coil and then, during winding, the shuttle pays out the wire and lays the wire on the bobbin. During loading and winding the shuttle is rotated so that it passes within the hole of the toroidal core.
In one type of coil winding machine, generally called a "precision coil winder", tension is maintained on the wire at all times so that the wire may be laid in an exact predetermined pattern, generally side-by-side, to form an evenly spaced coil. In conventional coil winding machines, the wire is transported from the shuttle to the core over a roller. The roller, which is relatively small, imposes a sharp curve on the wire as the wire passed over the roller. This has not been a problem because generally the wire is of a relatively small diameter and is sufficiently flexible so that it passes over the roller without imparting a permanent bend or adverse work hardening to the wire.
There are now new types of material which have improved electrical and magnetic characteristics for use in toroidal coils, one type being an amorphous (non-crystalline) metal.
It has been suggested that metals may be used in the form of tape to wind a core. However, if the tape is subjected to physical stress on the tape, the tape may be adversely affected in its magnetic properties. It has also been suggested that the new type of metal may be used as the core of a toroidal coil. Generally the metal cores are formed of thin sheets, which are electrically insulated from each other, to form a laminate. However, in some cases, such as an amorphous metal, the core presents an additional problem. It is relatively fragile in the sense that if physical stress is applied to the core, by tightly winding the wire about the leg of the core, the magnetic and electrical properties of the core are adversely affected. Consequently, the core should be wound as if it were an "air core", without imposing any physical stress to the core itself.
It has been suggested that a very heavy wire be used to form a coil in one leg of a transformer toroidal core. The wire is preferably rectangular in cross-section and, for example, is applied to form the primary winding of the transformer. In one embodiment the wire is formed in multiple layers.
In a conventional coil winding machine the wire is laid in the shuttle layer upon layer to form a circular coil of wire in the shuttle magazine. The wire is then removed from the top layer, i.e., from the outer diameter of the coil. In the case of a heavy wire or a tape, the removal from the top layer will impose a physical stress on the underneath layers, which stress may adversely affect the electrical and/or magnetic properties of the wire or tape.